Tancredo wrote:And I should have said ..why ma is short (according with my scansion), since it is followed by a double consonant... I do not know if there is another rule which prevails over the one I mentioned.

Ah. To the Greeks the aspirated consonants ([face=spionic]q, f, x[/face]) are single consonant sounds (unlike [face=spionic]z, c, y[/face]). Even though we usually transcribe them th, ph, ch, they scan singly.